A Self-report inventory is a type of psychological test in which a patient fills out a survey or questionnaire with or without the help of a mental health professional. Self-report inventories often ask direct questions about symptoms, behaviors, and personality traits associated with one or many mental disorders or personality types in order to easily gain insight into a patient's personality or illness. Most self-report inventories can be taken or administered within five to 15 minutes, although some, like the MMPI, can take up to three hours to fully complete.

The biggest problem with self-report inventories is that patients may exaggerate symptoms in order to make their situation seem worse, or they may under-report the severity or frequency of symptoms in order to minimize their problems. For this reason, self-report inventories should be used only for measuring for symptom change and severity and should never be solely used to diagnose a mental disorder. Clinical discretion is advised for all self-report inventories.

Many personality tests, such as the MMPI or the MBTI are designed to make it very difficult for a person to exaggerate traits and symptoms. However, these tests suffer from the inherent problems associated with personality theory and testing, in that personality is a fluid concept that can be difficult to define. Most personality inventories are based on a particular personality theory.m